The present invention relates generally to shingle cutting machines, and more particularly to a feed system that can be used in combination with a band saw or the like for the lengthwise cutting of shake slabs to produce resawn tapered shake shingles.
In the past, shake-type shingles were formed by manually splitting slabs of wood along their grain. Apparatus for mechanizing this procedure is disclosed in U.S. Pat. No. 3,407,855 to Richey. To enable these shake shingles to overlap one another evenly, a draw knife was used to remove irregularities of the natural split surfaces and to impart a taper to the shingle.
In U.S. Pat. No. 1,593,800, King described an improved method of making tapered shingles by sawing the slabs diagonally along their thickness to form two tapered shingles simultaneously. Originally, King's method was performed manually, but the method has since been automated to some extent by the use of apparatus described in U.S. Patents to Hutchings, U.S. Pat. No. 1,976,171, and Boullet, U.S. Pat. No. 3,171,450. In each of these designs, the slabs are sawn diagonally widthwise by a band saw, the slabs being oriented so that one of their long, narrow side faces, rather than an end face, is directed toward the blade of the saw.
Because they cannot cut slabs lengthwise to produce tapered shakes, the utility of these designs is limited by the physical configuration of the slabs. The slab can have uneven or corrugated surfaces, can be of variable thickness, and can be curved or warped along their length. Although the design of Boullet is calculated to accommodate slabs of varying thickness, it is impractical for cutting uneven surfaced, twisted, warped or curved slabs. Two shingles cut from such a slab can have substantially different thicknesses and individual shingles are often unevenly tapered along their length. Many such shingles are unusable and must be discarded.
Consequently, the practice of manually supporting and feeding slabs lengthwise into a band saw continues to be widely used. Obviously, this method is not only slow and tedious, it is a very expensive and dangerous way to produce shingles.
It would be preferable to have an automatic shake slab feeding apparatus for use with a band saw that would produce accurately tapered shake shingles from uneven-surfaced slabs that can be of varied thickness and can be curved, twisted or warped along their length.